ICAO Doc 4444
Chapter 5. Separation Methods and Minima

5.8.5 Opposite direction
When using wake turbulence categories contained in Chapter 4, 4.9.1.1 for a heavier aircraft making a low or a missed approach and when the lighter aircraft is:

a) using an opposite-direction runway for take-off, or
b) landing on the same runway in the opposite direction, or on a parallel opposite-direction runway separated by less than 760 m (2 500 ft) the following minimum separations shall be used:

1) between a HEAVY aircraft and a SUPER aircraft - 3 minutes;
2) between a LIGHT or MEDIUM aircraft and a SUPER aircraft - 4 minutes;
3) between a LIGHT or MEDIUM aircraft and a HEAVY aircraft - 3 minutes.